The Johnson & Johnson shot is teetering on the precipice of becoming America’s “dudes only” vaccine. On Tuesday, the CDC and FDA advised halting the vaccine’s nationwide rollout to investigate six cases of a rare blood-clotting disorder that’s occurred in people within about two weeks of receiving the vaccine—all of them women under the age of 50. In an emergency meeting convened Wednesday by the CDC, experts raised the possibility of limiting its future use to males, reserving Johnson & Johnson’s vaccine, as some have unfortunately put it, for johnsons alone.
That idea, crude though it may be, has something to it. The demographic pattern that’s emerged is striking, and many of the experts I talked with this week told me they suspect that, if the vaccine is ultimately linked to these clots, the relationship will come with a clear-cut sex or gender difference too. (These questions are also being debated with regard to the AstraZeneca vaccine, which contains comparable ingredients and might very rarely cause a similar or identical type of clotting disorder.)
But health officials have strongly cautioned that it’s too early to tell for certain whether a specific subset of the population is at increased risk of this clotting disorder; scientists haven’t even definitively pinpointed the J&J shot as its cause. Prematurely masculinizing the J&J vaccine could not only reinforce biases that compromise health care, but also run counter to one of the most important goals of the ongoing pause: identifying what factors, if any, do contribute to these unusual clots, and protecting the people they affect.
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The post-vaccination clots under investigation belong to a class called cerebral venous sinus thrombosis (CVST), and they seem to manifest when antibodies, perhaps produced in response to the shots, inadvertently rile up platelets in the blood. Platelets exist to keep wounds from bleeding indefinitely: They clump blood cells and proteins together to plug up leaks. But in CVST, they seem to spark a clotting cascade that can clog veins in dangerous places, including the brain, and lead platelet levels to plunge. The disorder is a collision between a powerful immune response and a naturally clot-prone environment; a potentially simple explanation for why they might show up more in women is that the hormone estrogen can amp up both of these factors.
Estrogen has many jobs in the body, and in a lot of contexts, it’s an instigator: It can boost a person’s propensity to clot, and it can goad immune cells into responding more vigorously to pathogens and vaccines. (There’s also some evidence that having two X chromosomes can make immune systems more reactive.) CVSTs are rare among the general population, but are more common in women. Menaka Pai, a hematologist who specializes in blood clots at McMaster University, in Ontario, likens clotting to falling off a cliff; estrogen, among other things, “pushes us closer to the edge.”
Estrogen and chromosomes aren’t the only variables here, though. Physiology undoubtedly influences a person’s responses to diseases, treatments, and vaccines, but behavior and social factors can, too. In recent weeks, dozens of similar CVST cases have cropped up amid millions of doses of the AstraZeneca shot (which hasn’t yet been green-lit in the United States). As with the J&J effect, most of these cases involved younger women. But in certain countries, women also made up the majority of people who were inoculated early on, weakening the clots’ link with gender. Some experts I talked with also noted that women tend to stay in more frequent contact with their health-care providers than do men, and might feel less wary about reporting unusual side effects or symptoms after getting a vaccine.
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If researchers confirm that these two vaccines are operating in similar ways, “being older, being a man—that’s not going to protect you,” Pai told me. In addition to the six cases in women, researchers are now reevaluating a potentially similar CVST case that was identified in a young man who had received J&J’s vaccine during the company’s late-stage clinical trials. Still, the extreme gender trend in the early J&J reports has been hard to ignore. Prior to the pause, roughly equal numbers of men and women had received the company’s shot, according to the CDC. I asked Alfred Lee, a hematologist at Yale New Haven Hospital, how often his discussions with colleagues about the clotting disorder had turned to the topic of sex or gender since Tuesday’s news broke. “Literally almost every single one,” he told me. Lee and his team are now being particularly vigilant about monitoring their recently vaccinated female patients, especially those taking estrogen-containing oral contraceptive pills—the group of people they’ve deemed to be “high-risk right now,” he said.
It’s heartening, several people told me, to see the possibility of sex and gender differences in vaccine side effects being openly acknowledged and addressed. For years, gender norms have influenced health-care providers in ways that haven’t served patients well—by dismissing women’s “hysterical” complaints of pain, for instance, or accusing them of falsifying their symptoms. But grabbing onto a still-tenuous link between sex and certain side effects could create problems, too. The seemingly obvious culprit of estrogen, for example, could end up obscuring some more obtuse cause. Sarah Richardson, the director of the Harvard GenderSci Lab, pointed me to the case of the sleep aid zolpidem, also known by its brand name Ambien. In 2013, the FDA recommended that women should receive a lower dose of the drug than men. The agency claimed that women’s bodies were more sluggish at clearing Ambien, leaving female users more cognitively impaired eight hours after ingesting it. That analysis later turned out to be flawed and incomplete, in part because the agency hadn’t properly accounted for differences in body weight; the drug wasn’t leaving all women worse off. “There isn’t any scientific evidence supporting sex-based dosage for zolpidem,” Richardson wrote in a 2019 op-ed for The Washington Post. Ambien, once hailed as a “flagship example of how sex differences can influence health,” she wrote, has morphed into a cautionary tale.
To truly home in on what’s at play with the Johnson & Johnson vaccine, Richardson told me, researchers will need to consider factors such as age, sex, gender, race, ethnicity, medical history, even social norms around how unusual symptoms are reported to health-care providers, and figure out how these variables intersect. That work is extraordinarily hard to do with just a handful of people, a likely reason the vaccine’s pause has been prolonged—so more data could be collected and analyzed. “People are really interested in the gender thing,” Lee, of Yale, told me. “But we can’t prove it yet.” That’s in part why a universal halt—one that didn’t segregate by gender, age, or any other demographic—was probably “the right approach” for now, Janna Shapiro, who studies sex differences in immune responses at Johns Hopkins University, told me.
Categorizing these clotting events incorrectly or too early also comes with dangers. The repetitive association of women and clots could stoke vaccine hesitancy in skewed ways. One recent poll showed that public confidence in the safety of the J&J vaccine plunged after the pause, and Elaine Hernandez, a medical sociologist at Indiana University, told me she’s concerned that reluctance about vaccines might concentrate among certain subgroups of women. She and her colleagues have found that young women who are Black and Latinx—groups that already have more limited access to vaccines—are more wary of getting immunized than their white peers.
Pushing this association too hard and too quickly could also skew data collection. Health workers could narrow their clinical lens; women might scour themselves for symptoms, while men and other people who don’t identify as women “may not take the symptoms [of CVST] seriously,” Krutika Kuppalli, an infectious-disease physician and vaccine expert at the Medical University of South Carolina, told me. That bell could be especially tough to un-ring in a culture where masculinity is so often considered incompatible with sickness. “People want to appear strong and tough, men in particular,” Hernandez told me. “There are already social pressures to not complain.” Casting the clotting condition as a “female problem” too early means donning blinders. “That’s troubling for the objectivity of the investigation going forward,” Richardson, of Harvard, said. (There’s still a paucity of data on whether transgender, intersex, or nonbinary people, especially those who are on hormonal therapies, might be vulnerable to unique vaccine side effects.)
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If a clear sex or gender difference does emerge, nuanced messaging will be necessary. As coronavirus cases surge, the risk of taking the vaccine might still be relatively low, especially in parts of the country where the fragile Pfizer and Moderna vaccines are harder to store and administer. Restricting the vaccine to certain age or gender groups could seed equity issues, both in the U.S. and internationally, or trigger repeated rounds of sociopolitical fallout. Shapiro pointed to the HPV vaccine, which was initially targeted to adolescent girls. The shots are now recommended for children of all genders, but misperceptions of the early rollout stigmatized the mostly female preteens who signed up for the shots as promiscuous, and the sole bearers of disease.
The goal in the coming days and weeks, Pai told me, is to appropriately titrate expectations of risk—to address concerns, but also avoid sensationalizing them. Our understanding of the clots’ danger could shift quickly as more data are collected. The dangers implied by six cases of a rare clotting disorder out of the roughly 7 million Americans who have received the J&J shot is much lower than the risk implied by six cases within the smaller population of the 1.4 million vaccinees who are women under 50. But now that physicians know what to look for, the numerator in that ratio will likely change as well. More cases will certainly appear, spanning a wider range of genders, ages, races, and ethnicities. These shifting odds will be easier to communicate if our lens isn’t unnecessarily narrowed: Expanding the definition of an at-risk population is harder than paring it down.
The suspension might already seem frustratingly long to some; plenty of people have called it out as cowardly and unwise, and questioned why federal officials prolonged it. But nearly everyone I’ve spoken with this week has praised the move as prudent, during a time of great uncertainty about who’s most at risk. “Ideally, we find out over time which vaccines are best for which groups, and why,” Leana Wen, an emergency physician affiliated with George Washington University, told me. “That’s the positive way of seeing this—this is in part the kind of information we’re getting here.”
Despite weeks of growing vaccinations and good news, headlines about blood clots and a “pause” in deploying the much-anticipated Johnson & Johnson shots have people worried.
Atlantic science writer Katherine J. Wu joins hosts James Hamblin and Maeve Higgins on the podcast Social Distance to explain the situation. Listen to their conversation here:
What follows is a transcript of their conversation, edited for length and clarity:
Maeve Higgins: You wrote about the Johnson & Johnson vaccine pause recently. Could you fill us in on what happened?
Katherine J. Wu: First, to put it in perspective: This was identified very quickly and then addressed very quickly. And that is all a good thing. But basically the situation is: The CDC and FDA reported that they had picked up on six cases of a very specific kind of blood clot in six women under the age of 50. They detected the blood clot in these women within about two weeks of when they had gotten their Johnson & Johnson vaccine. And this is out of nearly 7 million people in the United States who have gotten these vaccines.
So it is a very, very low number of cases so far. More certainly could emerge. But this was enough for federal health officials to say: Hey, this is concerning. We are seeing really the same problem arising in all six of these people. We should stop and take a look. And to be really clear here, what’s going on is a pause. They are literally hitting the pause button here and saying: Let’s get some time, evaluate the data, consult our experts, figure out what’s going on, and critically give doctors the information they need to detect these symptoms in patients and then treat them with the right therapies.
This is not a revocation of the emergency authorization. This is not a withdrawal. This is not like a full recall. This is just: “Let’s wait and see what happens here. Hopefully we’ll have more information to you very soon.”
James Hamblin: Do you have a sense of how confident regulators feel that these clots are indeed related to the vaccine?
Wu: My pulse on the situation is that there’s a moderately confident link at this point. Part of the point of the meetings is to really see how strong that link is, so I can’t conclusively say it, but I think there’s kind of a bump in confidence right now because what they’re detecting with these specific clots looks a lot like what has been going on with the AstraZeneca vaccine, which in terms of vaccine recipe, looks pretty similar to the J&J vaccine. And it’s probably not a complete coincidence that we’re seeing the same side effect appear shortly after both of these very similar-looking vaccines. I think they probably acted more swiftly here with J&J because of what’s already been going on with AstraZeneca.
Hamblin: Yeah, that makes sense. These are both adenoviral vector vaccines, so there are some similarities. AstraZeneca has been associated with clots in Europe, and so it seems like there is a low threshold here. And these specifically were clots in the cerebral veins.
Wu: Yeah, what’s going on here is a very, very specific kind of blood clot. Blood clots happen all the time. These are especially concerning because it’s a super-specific kind of blood clot … appearing in combination with low platelet counts. That’s another linked phenomenon that’s led a lot of researchers to hypothesize something is going on. And that specific combination has raised some eyebrows.
[It’s also] been seen also in response to, ironically, a blood-thinning drug called heparin. And that’s really important to know because heparin is one of the most common blood thinners that doctors use to treat clots. In this specific case, officials are recommending against using heparin because it could potentially make the situation worse. And I think that’s another plus of the pause. Doctors are getting the message loud and clear. Let’s not use it until we really know more and maybe never again for this specific condition.
Hamblin: Right, part of the pause is to help doctors understand what to look for and how to deal with symptoms that might be related to a clot like this. And part of it seems to be messaging to patients who are within this window of having recently had a Johnson & Johnson vaccine. If people experience basically any neurologic symptoms—from dizziness and headaches to anything more significant than that—contact a physician, because it’s going to be especially important to keep a close eye on things like that.
Higgins: [In your piece] you quoted Dr. Angie Rasmussen, an amazing virologist we’ve had on Social Distance before. She got the Johnson & Johnson vaccine nine days ago as we tape, and she’s in the age range of the six women who got the blood-clotting symptoms. So what was her take as a person who got the vaccine and also just as a virologist?
Wu: She had been tweeting about this, and I knew she would provide some really balanced perspective here. First things first: She has gotten the vaccine. There is really no undoing that. But she’s not spending all of her time worrying about getting a clot—partly because that won’t affect whether or not she does—but also because these cases have so far been really, really rare. I don’t think we yet have enough information to say they’re going to appear in exactly X percentage of people, but it’s probably going to be an extraordinarily low number.
Higgins: What are the symptoms to look for in that very rare case?
Wu: There’s a list that the CDC and FDA put out. They said if you develop severe headaches, abdominal pain, leg pain, or shortness of breath within three weeks of your injection, reach out to your health-care provider. But that is going to be the next level up from the expected side effects that some people might get within the first couple of days after getting their injection, which might include a mild headache. So there’s a little bit of subjectivity there, but hopefully people are just keeping an eye out in those three weeks. That’s the critical window we’re looking at here.
Hamblin: Do you think this has been handled correctly? Do you think pausing Johnson & Johnson for everyone was the right move?
Wu: That’s a tricky question to answer, but I think I lean on the side of “yes.” Imagine if the CDC and FDA had waited until it was 20 cases, or 30 cases, or 100 cases … [they] would have gotten questions about why they didn’t pause it when it was just six and we could have prevented 94 more cases.
I think they saw a signal and not just a random cluster of blood clots [that] all looked so similar in this demographic slice of the population. And so they acted quickly. This pause could just be a matter of days to get clarity and make sure that people are aware and looking out for it. I wouldn’t be surprised if more cases come up because we now know to look for it. [But] they are not hoping to permanently derail this vaccine.
Hamblin: Do you think this pause—assuming it doesn’t pan out to be over a major risk factor and Johnson & Johnson gets back online—will, over time, lead to vaccine hesitancy of the sort that we’ve seen with AstraZeneca in Europe? How concerned are you about it exacerbating what we’ve already seen in the U.S.?
Wu: I am concerned about this, but I don’t want to jump to conclusions about how hesitancy will be affected. It’s so tricky because exacerbating hesitancy can occur in a multitude of ways. One is: People hear something negative about the vaccine and they feel less good about taking it. Another is that experts conceal something about the vaccine and the public feels like they’re not being trusted with the relevant information.
The CDC and FDA are in a bit of a “damned if you do, damned if you don’t” situation, but I’ve been really impressed with how a lot of experts have tried to communicate the situation as clearly as they can, and really stress the point that we can make better-informed decisions with this information being publicly out there.
That said, I have spoken to a few people who have already said someone in their life was signed up to get this vaccine and now aren’t feeling as great about getting this one in particular, but they’re also not feeling very good about the other vaccines.
Higgins: I also read your story about second-dose side effects. Our producer Kevin Townsend got his second shot last week, and he was really knocked out. Have you heard from a lot of people who’ve had this tough ride?
Wu: What’s so interesting about this whole vaccine rollout is we’re really coming to grips with just the diversity of the human experience. I’ve talked to people who have had no side effects whatsoever—my mom was actually one of them—[to people like] my husband, who had really bad side effects to both injections. And they are both totally fine. I feel great about both of them being protected.
That said, when there is a second dose, it does seem to, on average, pack a bigger punch. And I think that can be chalked up to the fact that that second dose is a reminder for the immune system about what it’s already seen. You’re just going to rile up the immune system a little more.
The second time you annoy someone, they’re going to yell at you a little louder. And I think that’s roughly equivalent to what’s happening here. I do think it’s a comforting and visible sign that the process is working as expected, but I also don’t think people should worry if they don’t have side effects. Something else that’s comforting is that we did see a lot of side effects documented in the clinical trials. So this was not a surprise. We saw this coming. But the percentage of people who were protected from COVID-19 far exceeded the percentage of people who had tons of side effects. And so, you can have a ton of different experiences in those first few hours after the shot, but don’t read too much into it.
Hamblin: I have a little soreness in my arm, and I take it as evidence that it’s working, that I’m gaining this protection. And the side effects you’re talking about after a second dose are mostly: low energy, fever, aches, chills, occasionally rashes … but they go away pretty quickly. This is nothing like getting COVID-19, nothing like even getting the flu.
Wu: Exactly. It’s like the body reacting to the idea of a pathogen. People have said it’s like having 24 hours of flu-like symptoms, but you’re exactly right—it is not equivalent and certainly not worse than getting COVID-19. The risk calculation here is absolutely clear-cut.
A year ago, when the United States decided to go big on vaccines, it bet on nearly every horse, investing in a spectrum of technologies. The safest bets, in a way, repurposed the technology behind existing vaccines, such as protein-based ones for tetanus or hepatitis B. The medium bets were on vaccines made by Johnson & Johnson and AstraZeneca, which use adenovirus vectors, a technology that had been tested before but not deployed on a large scale. The long shots were based on the use of mRNA, the newest and most unproven technology.
The protein-based vaccines have moved too slowly to matter so far. J&J’s and AstraZeneca’s vaccines are effective at preventing COVID-19—but a small number of recipients have developed a rare type of blood clot that appears to be linked to the adenovirus technology and may ultimately limit those shots’ use. Meanwhile, with more than 180 million doses administered in the U.S, the mRNA vaccines have proved astonishingly effective and extremely safe. The unusual blood clots have not appeared with Pfizer’s or Moderna’s mRNA technology. A year later, the risky bet definitely looks like a good one.
The U.S. has ordered enough mRNA vaccines to inoculate its entire population. In that context, the CDC and FDA’s call to pause the J&J rollout this week is a blow to the American inoculation campaign, but hardly a devastating one. (J&J’s vaccine accounts for less than 5 percent of doses administered so far, and AstraZeneca’s has not yet been authorized in the U.S.) But the rest of the world has been banking on the J&J and AstraZeneca vaccines, which are both cheaper and easier to distribute because they don’t require the same cold storage as mRNA vaccines. If the blood-clot risk is real, the divide between the mRNA-vaccine haves and have-nots will only grow. The U.S. will be fine; the rest of the world will face difficult questions about balancing the risks and benefits of an affordable, good-but-not-best vaccine against a disease that has killed nearly 3 million people.
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The blood-clot events with the AstraZeneca and J&J vaccines are so rare—appearing in one in 100,000 to one in 1 million vaccine recipients—that they would not have shown up in clinical trials, even ones conducted within more leisurely, non-pandemic timelines. (The COVID-19 vaccine trials, which generally included tens of thousands of participants each, were actually unusually large because researchers wanted data as quickly as possible.) “It’s true with all new medications of any sort. You only find rare events when things are rolled out to very vast numbers of people,” says John Grabenstein, the associate director of scientific communication for the Immunization Action Coalition, who used to work on vaccines for the pharmaceutical giant Merck. “One-in-a-million events are just barely measurable.” That faint signal is especially difficult to see against a noisy background: Some people get blood clots for reasons unrelated to the vaccine, too.
In Europe, the strange nature of these blood clots tipped doctors off to a possible link to AstraZeneca’s vaccine. The patients with clots also had low numbers of platelets, which are tiny blood cells that help with clotting. Normally, someone with a low platelet count cannot form clots and bleeds as a result. But in these people, who had all recently gotten an AstraZeneca shot, an immune reaction may have set off uncontrolled clotting that bound up all their platelets.
Some scientists now hypothesize that the immune reaction is triggered by some part of the adenovirus-vector technology. If that’s true, these blood clots might show up as a rare side effect with other adenovirus-vector vaccines. But they clearly are very infrequent. The AstraZeneca and J&J coronavirus vaccines are the first adenovirus-vector shots to even be deployed widely enough in the U.S. and Europe for such rare events to emerge, but vaccines including Russia’s Sputnik V, China’s CanSino, and J&J’s Ebola vaccine also use the technology.
[Read: 3 different futures for the Johnson & Johnson vaccine]
mRNA vaccines are similarly new, but they have so far racked up a good safety record. So many doses have been administered that these unusual blood clots—or any serious one-in-a-million event—would very likely have shown up by now. Back in December, experts quickly noticed and warned the public about a handful of severe allergic reactions to the Pfizer-BioNTech and Moderna vaccines, which is why vaccination sites now monitor recipients for 15 to 30 minutes after the jab. In addition, doctors have picked up on a possible one-in-a-million risk of a bleeding disorder called immune thrombocytopenia, which happens when the immune system attacks platelets after vaccination. (It’s a rare but documented side effect of some other vaccines, such as the one against measles.) These patients do have low platelet counts, but they do not have the accompanying blood clots that seem unique to adenovirus-vector vaccines.
Immune thrombocytopenia is easily diagnosed and treated, James Bussel, a pediatrics professor at Weill Cornell Medicine who studies the condition, told me in an email. But the unusual combination of blood clots and low platelets is trickier. For example, one standard treatment for clots is a blood thinner called heparin, but the drug can, in very rare cases, cause the exact combination of low platelets and blood clots that doctors are concerned about. Experts now fear that heparin might make the potential vaccine reaction even worse. This combined condition also seems to be more dangerous than immune thrombocytopenia, but the prognosis may improve as more doctors learn how to treat it.
U.S. officials expect the J&J pause to last no more than a few days, as experts review the safety data and potentially revise recommendations. After a similar pause and review of the AstraZeneca data in Europe, several countries restricted that vaccine to older residents. (Most of the 86 blood-clot cases observed with the AstraZeneca vaccine in Europe were in women under 60, as were all six cases observed with the J&J vaccine in the U.S.) The U.K. now recommends that people younger than 30 be offered a different vaccine if possible.
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The recommendations take into account individual risk: For older people at high risk of severe COVID-19 complications, the benefits of the vaccine clearly outweigh the risks of a blood clot. But for young people at lower risk from the coronavirus, the benefits are not so clear. For regulators, that balance also depends on whether a country has any other vaccines available and the severity of its local COVID-19 outbreak. The European Union and the U.K. do not have as many mRNA vaccines as the U.S., and less wealthy nations have even less supply. Ultimately, every country will have to do its own benefit-risk calculation.
The U.S.’s recommendations may end up diverging from other countries’, but they may also influence them. Sean O’Leary, a pediatrician at the University of Colorado and a liaison to the CDC’s Advisory Committee on Immunization Practices, notes two historical examples. Although the United States has discontinued use of the oral polio vaccine—which is more effective and easier to administer than the shot, but also carries a one in 2.5 million risk of paralysis after infection with the live virus in the oral vaccine—the World Health Organization continues to recommend it in countries where polio is endemic. But when the U.S. in 1999 stopped using a vaccine against rotavirus because of rare reports of intestinal blockage, the rest of the world fell in line, despite the fact that the virus was killing about half a million kids worldwide each year. “The decision was made, essentially, if it’s not good enough for you, it’s not good enough for us,” O’Leary says. Eventually, two newer rotavirus vaccines with a lower risk of complications were developed. They are now used in the U.S. and around the world.
With rotavirus, the vaccine conundrum became moot as new alternatives became available. With COVID-19, those alternatives already exist in the form of mRNA vaccines. There was no guarantee that the mRNA shots would be ready so quickly, or turn out to be so good and so safe. That they did is a great stroke of luck. But in the near future, the Pfizer and Moderna vaccines’ limited supply, high price, and distribution challenges will make them functionally unavailable to much of the world. The U.S. can afford, literally, to vaccinate most of its population with Pfizer’s and Moderna’s vaccines. Most other countries cannot.
The Johnson & Johnson vaccine has entered regulatory purgatory. This morning, the CDC and FDA jointly recommended, “out of an abundance of caution,” a nationwide halt to the single shot’s rollout. The two agencies are investigating a rare blood-clotting disorder: In the six cases reported so far, all in the United States, women ages 18 to 48 developed an unusual type of blood clot within about two weeks of receiving the company’s inoculation.
Experts haven’t yet conclusively determined whether J&J’s vaccine is directly causing these strange clots, or how frequently the condition might be occurring, because they’re relying largely on people reporting their health conditions to federal agencies. Roughly 7 million doses of the vaccine have been administered so far in the United States; among them were about 1 million women under the age of 50. “I think it’s reasonable to say it is a rare event, but I don’t think we should go into false precision in this kind of situation,” Saad Omer, a vaccine expert at Yale, told me. “Our numerators and denominators are still emerging.”
Though the pause isn’t mandatory, most states have decided to temporarily pull the J&J vaccine and replace it with shots made by Moderna and Pfizer-BioNTech—neither of which has been associated with clots—when possible. The announcement has, within a matter of hours, trapped past and future recipients of J&J’s jabs in an uneasy limbo.
Still, this particular in-between place has an exit, and the situation is in many respects more reassuring than not. I talked with 12 people today, including one who had recently received the J&J shot and several others who had originally intended to. They all struck a similar note: The pause is a reflection, they told me, of federal regulation in action—responding to even the tiniest hint of a safety issue, in case it blossoms into something serious. In similar situations, other vaccines have been subject to the same scrutiny; it’s not that uncommon for products to hit roadblocks after initial clearance. “I’m somewhat concerned, but I’m not freaking out,” Omer said. With the right monitoring systems in place, investigations like this can and should happen, with transparency. “This is the system working as intended,” Natalie Dean, a biostatistician at the University of Florida who studies vaccine trials, told me. “We’re paying close attention to even these exceedingly rare outcomes.”
People who have already gotten the J&J vaccine absolutely shouldn’t panic, especially if more than a month has passed since they received their dose. So far, the incidents documented seem to be occurring with the first couple of weeks post-vaccination. The CDC and FDA recommend that recent recipients should contact their health-care provider if they develop severe headaches, abdominal pain, leg pain, or shortness of breath within three weeks of their injection. (Those worrisome symptoms shouldn’t be confused with the mild headaches, aches, and other flulike symptoms that commonly arise as side effects within the first couple of days of any COVID-19 vaccine.) Adverse effects also don’t detract from a vaccine’s effectiveness at preventing COVID-19, so there’s no need to seek out another vaccine to supplant J&J’s.
Angela Rasmussen, a virologist affiliated with Georgetown University, told me she received J&J’s vaccine eight days ago, which puts her squarely in this sensitive window. She also falls within the age range of the women who reported post-vaccination clotting. She’ll be on the lookout for any unusual symptoms, but is “keeping it all in perspective,” she said. Even if experts do determine that the vaccines are at the root of these clots, they are probably very, very rare. “If I thought I was going to get a blood clot, I would also buy a lottery ticket,” Rasmussen told me.
Blood-clotting disorders, should they ultimately be tied to this vaccine, won’t necessarily end Johnson & Johnson’s current efforts at COVID-19 immunization. Certain types of estrogen-containing oral contraceptives and hormone therapies carry similar concerns, but have yet to be pulled from the market. (Rasmussen told me that those potential side effects didn’t stop her from using oral birth control for the better part of 20 years.)
The clots reported after J&J immunization—called cerebral venous sinus thromboses—are in an unusual class. A very similar clotting problem has been reported after injections of AstraZeneca’s COVID-19 vaccine, which strongly resembles the J&J shot in formulation; several European countries have restricted the AstraZeneca shot to use in older adults only. One benefit of publicizing the potential problem with J&J right now is that federal health officials can alert doctors to the right treatments. They have advised against deploying heparin, one of the most common blood thinners prescribed for clots, in these patients, because it has the potential to exacerbate this specific condition. Luckily, an entire arsenal of alternative treatments exists. “It’s really important to know what to be looking for right now,” Céline Gounder, an infectious-disease physician at Bellevue Hospital in New York, where some patients have been receiving the J&J vaccine upon discharge, told me.
For people still waiting to get vaccinated, the pause could introduce some temporary, regional speed bumps into the rollout. But Johnson & Johnson shots already made up a minority of the injections being doled out to Americans, and supply has sputtered because of a recent factory snafu that compromised up to 15 million doses. Many people who were signed up for these shots in the near future should be able to switch to an mRNA-based alternative. (I was signed up to get a J&J shot this week; I’ll be getting Pfizer instead.) The CDC and FDA are also expected to issue updates within the next few days, leaving open the possibility that vaccines will continue largely on schedule thereafter.
The forecast further out is murky. A panel of experts must now determine whether the vaccine and these clots are conclusively linked. This will involve comparing the rate at which blood clots occur shortly after a J&J vaccination to their incidence in the general, uninoculated population. These cases could still be chalked up to coincidence, or possibly to an unidentified underlying condition that afflicted all six women. Clinical trials found the J&J vaccine to be safe as well as effective; that verdict could certainly hold after this new round of federal vetting. Pauses, Omer told me, aren’t revocations or excoriations of a product. Instead, they make space for experts to suss out a situation and revise the playbook as needed.
“Hopefully one outcome would be that we develop a better understanding of this issue, and who’s specifically at risk,” Dean told me.
If researchers establish that there is a risk relationship, they’ll next need to determine its extent, and weigh it against the relative risk of remaining unvaccinated. Since the start of the pandemic, the coronavirus has killed nearly 3 million people around the globe, and saddled many thousands of others with lasting, debilitating symptoms. Contracting the coronavirus, too, has been linked to blood clots, which appear, by some estimates, in about 20 percent of COVID-19 patients, and 31 percent of patients who end up in intensive care. Several experts told me that they’d need to see many, many more clotting events to even consider pulling an otherwise highly successful and effective vaccine from the global market, especially while many countries struggle to acquire, store, and administer vaccines.
A Johnson & Johnson recall would be “a disaster,” Rasmussen told me. “We need all the doses we can get.”
Strictly by the numbers, the United States could get by without Johnson & Johnson. Hopefully, it won’t have to. Federal regulators could follow the lead of their counterparts in Europe, who have recommended alternatives to the AstraZeneca vaccine for younger people; they could also add a cautionary clause specifically for cisgender women and certain transgender or intersex people who might be at higher risk.
Johnson & Johnson’s vaccine still has immense appeal. Unlike its two-dose Moderna and Pfizer counterparts, it’s a one-and-done shot—a potentially big boon for people who can’t easily travel to and from inoculation sites, or otherwise access the injections. Vials can also be stored at refrigerator temperatures for months, making the shots easier to ship to parts of the world with few resources. “We were really counting on these to help vaccinate the world,” Gounder told me, referring to J&J, AstraZeneca, and other shots with similar recipes.
Based on what we know so far, the future of the J&J vaccine can fork in at least three different directions. In one, the vaccine flames out; unless many, many more cases come to light soon, this seems unlikely. Either of the other two—in which officials end the pause and return the nation to its regularly scheduled vaccine programming, with or without restrictions on who gets J&J next—are more likely. No matter the outcome, though, today’s announcement won’t quickly be forgotten. Pauses in clinical trials, sprinkled through the past year, have already stoked vaccine hesitancy, skepticism, and outright denialism in many circles. The Johnson & Johnson vaccine, previously stigmatized for being “less effective,” now risks a second label: “less safe.” It’s on the precipice of becoming our country’s grody vaccine; maybe it’s already toppled over the edge. An altered reputation in the U.S. will reverberate throughout the world, and set back the global struggle to contain the coronavirus.
If the J&J vaccine does return with the FDA’s blessing, we’ll need to rehabilitate it with clear and nuanced messaging, Gounder and many others told me. A vaccine can be excellent. A vaccine can also carry risks. Both can be true; both have been true, for other shots we’ve used. In this case, the gamble could be very small—and still be well worth it.
The Atlantic’s COVID-19 coverage is supported by a grant from the Chan Zuckerberg Initiative.
Company has said it is postponing deployment in Europe following concerns about blood clots in US
The European commission has said it is seeking “urgent clarification” from Johnson & Johnson after the company’s “completely unexpected” announcement that it is delaying the deployment of its coronavirus vaccine across Europe following concerns in the US about a small number of blood clots.
After US health agencies recommended states temporarily halt use of the shot on Tuesday, Johnson & Johnson said in a statement it had been “reviewing these cases with European health authorities” and had “made the decision to proactively delay the rollout of our vaccine in Europe”. Continue reading...
South Africa's health regulator, on Saturday, recommended that the government lift the pause on administering drugmaker Johnson & Johnson's COVID-19 vaccines, given that certain conditions are
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Johnson & Johnson had reached out to rival Covid-19 vaccine makers to join in an effort to study the risks of blood clots, The Wall Street Journal reported on Friday, citing people familiar with the matter.AstraZeneca, which had been buffeted by similar blood clotting concerns for weeks, agreed, while Pfizer and Moderna executive declined, saying their vaccines appeared safe, the report said.The US federal health agencies had on Tuesday recommended pausing use of Johnson & Johnson’s vaccine for…
The European Union said it was expecting 50 million Pfizer coronavirus vaccine doses earlier than expected, as the United States said it would continue a pause in vaccinations using the Johnson & Johnson shot for at least another week so regulators could assess possible blood clot links.Rival drugmaker AstraZeneca faced a similar setback after Denmark banned its use, also over blood clot links.Concerns over using the J&J and AstraZeneca vaccines have dampened hopes that mass immunisations would…
U.S. health officials have delayed a decision on whether to resume the use of Johnson & Johnson's COVID-19 vaccine after reports of blood clots in six women who received doses. Dr. Monica Gandhi, an infectious disease physician and professor of medicine at the UCSF/San Francisco General Hospital, says it's "prudent" to investigate reports of blood clots but notes the issue "is very rare" and unlikely to cause more than a temporary delay. She also says it's important to raise "vaccine optimism" by continuing to tout the benefits of COVID-19 vaccines. "Eventually we are going to get back to the normalcy of not masking and distancing. We're just in this twilight period right now because we are not fully vaccinated," she says.
California and Los Angeles officials say they don't expect the Johnson & Johnson stoppage will make it harder right away to get a COVID vaccine.
Experts said that while the pause on Johnson & Johnson's vaccine may make sense for the U.S., stoppages in poorer countries would end up costing lives.
A CDC advisory panel is grappling with the best way to "do no harm" regarding Johnson & Johnson's COVID-19 vaccine and its risk of blood clots.
Reports of blood clots among those who got Johnson & Johnson's COVID-19 vaccine may make some recipients anxious. Here's how to handle those feelings.
U.S. officials called for a pause in the use of Johnson & Johnson's COVID-19 vaccine after serious blood clots were reported in six recipients.
A doctor and a public health student each say more context is needed to understand the decision to temporarily suspend vaccination with the Johnson & Johnson shot.
"If something that you read or see seems too good or too bad to be true, it probably is," infectious disease specialist and NowThis contributor Laurel Bristow says. Bristow discusses the Johnson & Johnson vaccine pause, suggesting that "the reason for the pause was really kind of lost in the drama and the scare."
Dr. Anthony Fauci tells CNN's Dana Bash that he believes the CDC and FDA will lift the Johnson & Johnson vaccine pause soon but may include "some sort of either warning or restriction."
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The FDA’s decision to pause the rollout of the Johnson & Johnson vaccine sparked criticism from across the spectrum that the administration was being too cautious.
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The advisory panel will discuss safety data related to a small number of blood-clotting cases in Johnson & Johnson vaccine recipients. It is unclear whether the vaccine was responsible for the clots.
Health departments scrambled to postpone vaccine clinics and rebook patients after the one-dose offering from Johnson & Johnson was sidelined.
Johnson & Johnson had reached out to rival COVID-19 vaccine makers to join in an effort to study the risks of blood clots, the Wall Street Journal reported on Friday, citing people familiar with the matter.
Europe's choppy vaccine rollout hit more trouble on Wednesday after U.S. drugmaker Johnson & Johnson delayed its COVID-19 shot and Denmark said it would drop a similar vaccine from AstraZeneca over the risk of blood clotting.
U.S. federal health agencies on Tuesday recommended pausing the use of Johnson & Johnson's COVID-19 vaccine after six women under 50 who had received it developed rare blood clots, dealing a fresh setback to efforts to tackle the pandemic.
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A pause in the distribution of the Johnson & Johnson vaccine will last at least another week, even as eligibility for coronavirus vaccines expand. What impact will the pause have on inoculations?
NPR's Debbie Elliott talks with hematologist Menaka Pai about the rare clotting disorders that have led to a pause in the distribution of the Johnson & Johnson vaccine in the U.S.
Which communities could suffer most from the Johnson & Johnson vaccination pause? NPR's Ailsa Chang talks to Dr. Paul Adamson, an infectious diseases fellow at David Geffen School of Medicine at UCLA.